Laryngeal electromyography.

Laryngeal electromyography (EMG) is simultaneously a powerful clinical and investigative tool. EMG may be diagnostic and prognostic in cases of laryngeal or vagus nerve injury and can differentiate between vocal cord fixation and paralysis. EMG also is being used to help unravel complex laryngeal neural and muscle physiology. Basic principles of EMG, techniques of EMG limited to three muscles--the thyroarytenoid, the posterior cricoarytenoid, and the cricothyroid, and pitfalls of this procedure are discussed within this article.